
<style>
	.scrollable-container{
		height: 100px;
		overflow-y: scroll;
	}
	.background {
		padding-top: 60px;
		height: 300px;
		background-image: url("https://zos.alipayobjects.com/rmsportal/RmjwQiJorKyobvI.jpg")
	}
</style>
<div class="scrollable-container" @ref="_container">
	<div class="background">
		<Affix Target="@_container">
			<Button Type="@ButtonType.Primary">
				Fixed at the top of container
			</Button>
		</Affix>
	</div>
</div>

@code{

        private ElementReference _container;
	}